When to make Chlorine?

[Theusla]

There is a difference in manually chlorinating a pool and using a SWG. When you add chlorine manually you add it all at once. With a SWG a little is being added through out the pump run time.
I run my pump for 8 hours in N FL ....5 hours from 10 am to 3 pm and then three more hours from 6 to 9 pm.

What is the advantage of doing a split run time?